PX4IO: Initialize all channels to zero
PX4IO: Initialize all channels to zero

This sets all channels to zero, including unused channels. Any consumer of the data using the channel count will not see a difference, but this is helpful to avoid confusion in log analysis.

Aerotenna/Firmware,mje-nz/PX4-Firmware,dagar/Firmware,acfloria/Firmware,Aerotenna/Firmware,Aerotenna/Firmware,dagar/Firmware,acfloria/Firmware,PX4/Firmware,mje-nz/PX4-Firmware,Aerotenna/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,PX4/Firmware,dagar/Firmware,acfloria/Firmware,Aerotenna/Firmware,krbeverx/Firmware,krbeverx/Firmware,dagar/Firmware,Aerotenna/Firmware,dagar/Firmware,krbeverx/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,krbeverx/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,Aerotenna/Firmware,PX4/Firmware,krbeverx/Firmware,dagar/Firmware,PX4/Firmware,dagar/Firmware,mje-nz/PX4-Firmware